#include<bits/stdc++.h>
using namespace std;
class Solution {
public:
	int peakIndexInMountainArray(vector<int>& arr) {
		int l=0,r=arr.size()-1;
		while(l<r)
		{
			int mid=l+(r-l+1)/2;
			if(arr[mid]>arr[mid-1]) l=mid;
			else r=mid-1;
		}
		return l;
	}
};
int main()
{
	
}
